/*
 * Copyright 2010 Assert Developments
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * 	http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject.factory;

import com.google.inject.Inject;
import com.google.inject.Injector;

/**
 * An abstract factory that creates instances using a guice injector.
 *
 * @author Stefan Bangels
 */
abstract class AbstractGuiceFactory<T> extends AbstractFactory<T> {

    @Inject
    protected Injector injector;

    /**
     * Set the guice injector
     *
     * @param injector the guice injector
     */
    @SuppressWarnings("unused")
    void setInjector(Injector injector) {
        this.injector = injector;
    }

    /**
     * Get an instance of the specified class using the guice injector.
     * This method throws an IllegalArgumentException when no injector has been defined.
     *
     * @param clazz the class
     * @return an instance of the specified class
     * @throws IllegalArgumentException when no injector has been defined
     */
    @Override
    protected final T getInstance(Class<? extends T> clazz) {
        if (injector == null) {
            throw new IllegalArgumentException("no injector defined");
        }
        return injector.getInstance(clazz);
    }

}
